Hilbert-Huang transform (HHT) is a very effective time-frequency analysis method, but it has some disadvantages. For example, the dense modal signal cannot be decomposed completely, and redundancy intrinsic mode functions (IMFs) are easy emerging at low frequency, which will cause the distortion of the processing results. In view of the above questions, this study applies the wavelet packet transform for denoising before HHT for improving the dense modal problem, and applies the correlation coefficient method to eliminate the redundancy IMF. The fault diagnostic case of roller bearing shows the effectiveness of the proposed method.
Serum- and glucocorticoid-inducible kinase 3 expression was more frequently observed as the nasopharyngeal epithelium progresses from normal tissue to carcinoma. This suggests that serum- and glucocorticoid-inducible kinase 3 contributes to the multistep process of NPC carcinogenesis. Serum- and glucocorticoid-inducible kinase 3 represents a target for nasopharyngeal carcinoma therapy, and a basis exists for the further investigation of this adjuvant treatment modality for nasopharyngeal carcinoma.
To explore the regularity of deformation and gas migration of coal seam, the author transmits signal of strain foil on coal samples in all directions by transforming oil plug, oil plug seal, heat shrink tubing and wire seal, based on the existing triaxial seepage device. We can complete coal deformation and gas seepage test with this device under different temperature, different stress, different gas stress and so on.
Based on the existing triaxial seepage equipment, this paper choose the type of 2XZ-4 vacuum pump to provide negative pressure, type of CHF100A-1R5G-4 of Wei teng Ying transducer to control and make a constant negative pressure, and choose glass flowmeter to measure the flow of coal bed gas to explore the gas migration in coal reservoir during gas drainage. The triaxial seepage equipment after transformation can provide steady negative pressures on the range of-0.075MPa to-0.085MPa.The laboratory tests showed that the equipment can be used to conduct triaxial seepage experiments at different effective stress, different temperature and other conditions for negative pressure at exit.
Using a self-developed triaxial seepage device, tests of coal samples from Liu Panshui coal mine were carried out to explore the relationship between permeability and pore pressure when effective stress and temperature conditions keep constant as well as the impact of pore pressure on gas seepage. The research results show that: Permeability decreases with the increase of pressure difference between inlet and outlet Δp when effective stress and temperature keep constant; permeability declines in a nonlinear tread with increase of pore pressure and they all have a exponential relationship; when pore pressure is low, permeability decreases faster with changes in pressure difference between inlet and outlet Δp. When gas pressure is low, with pore pressure increasing the gas flow pore narrowed.
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